The decyanation of substituted cyanamide derivatives represents an important process in synthetic organic chemistry. Typically, this process has been conducted by hydrolyzing the cyanamide in an aqueous acidic medium, but this method is not acceptable for acid labile substrates. Decyanation of cyanamides under alkaline conditions is known in certain instances, but is less preferred, in part because of handling problems which result in an eventual loss in yield of the desired product. See, e.g. Organic Synthesis Coll. Vol. I, 201-202 which provides a discussion of the decyanation of diallylcyanamide under acidic and basic conditions.
The present invention relates to a process for decyanating ergoline derivatives with an alkali metal hydroxide in an alcoholic solvent at an elevated temperature. Ergolines have been decyanated by treatment with zinc and acetic acid. See, e.g. U.S. Pat. No. 4,246,265. However, this procedure results in a significant yield reduction because of the formation of impurities, now believed caused by the acid lability of the ergoline substrate. The present process avoids this problem by synthesizing the desired compound in high yield and in pure form in a basic reaction mixture containing an alcoholic solvent.